Design considerations for a uni-traveling carrier traveling wave photo detector for efficient generation of millimeter wave and sub-MM wave signals

In this paper the generation of MM and sub-wave signals by heterodyning two optical signals in a photo detector is considered. Previous work in this field has shown that this approach is feasible. However, the work demonstrated so far exhibits very low power efficiency (<1%) and low output power level (<1 mw) for frequencies in the MM wave range. In this paper design considerations for an efficient traveling wave unitraveling carrier PD are presented. Simple calculations are presented to estimate the bandwidth, microwave output power and power efficiency of this type of PD. The effect of the physical design parameters on the performance is discussed and design approach for high efficiency is presented. It is also shown that including the electron ballistic effect in the model suggests operation of the PD well into the sub-MM range.